Index: playercode/mplayer.c
--- playercode/mplayer.c.orig
+++ playercode/mplayer.c
@@ -380,9 +380,9 @@ static SWORD StartEnvelope(ENVPR *t,UBYTE flg,UBYTE pt
 	}
 
 	/* Fit in the envelope, still */
-	if (t->a >= t->pts)
+	if (t->a >= t->pts && t->pts != 0)
 		t->a = t->pts - 1;
-	if (t->b >= t->pts)
+	if (t->b >= t->pts && t->pts != 0)
 		t->b = t->pts-1;
 
 	return t->env[t->a].val;
